Low-threshold operation of GaAs-based (GaIn)As/Ga(AsSb)/(GaIn)As W-quantum well lasers emitting in the O-band

TL;DR

This paper demonstrates low-threshold, high-efficiency GaAs-based W-quantum well lasers emitting in the O-band, achieved through optimized growth conditions, device design, and increased optical confinement, suitable for practical applications.

Contribution

The study introduces a scalable epitaxy process and device design improvements that significantly enhance performance of GaAs-based W-quantum well lasers emitting at 1.26 and 1.30 micrometers.

Findings

Differential efficiency up to 58% at 1.26 μm

Threshold current density as low as 0.16 kA/cm^2

Excellent temperature stability with T_0=72K and T_1=293K

Abstract

The influence of the growth conditions as well as the device design on the device performance of (GaIn)As/Ga(AsSb)/(GaIn)As "W"-quantum well lasers is investigated. To this purpose, the epitaxy process is scaled to full two inch substrates for improved homogeneity while the growth process is carried out in a single run for an improved quality. Furthermore, the optical confinement factor is increased by increasing the aluminum concentration within the cladding layers to a value of 65%. The procedure is carried out for devices with emission wavelengths of 1.26 micrometer as well as 1.30 micrometer. Differential efficiencies as high as 58% and threshold current densities as low as 0.16 kA/cm^2 are observed in case of devices emitting at 1.26 micrometer at room temperature. Furthermore, excellent characteristic temperatures of T_0=(72 plus minus 5)K and T_1=(293 plus minus 16) K are recorded in the temperature range between 10 degree Celsius and 100 degree Celsius. Devices emitting at 1.30 micrometer exhibit differential efficiencies of 31% and threshold current densities of 0.50 kA/cm^2 at room temperature. Further improvements of these properties and wavelength extension schemes are briefly discssused.